module S4_1_6 where average xs = sum xs / fromInt (length xs) average' xs = s / fromInt n where (s,n) = av xs av [] = (0,0) av (x:xs) = (x+s,n+1) where (s,n) = av xs average'' xs = av' xs 0 0 where av' [] s n = s / fromInt n av' (x:xs) s n = av' xs (x+s) (n+1)